League of Legends uses a system to match players with similar skill levels in games, and this system does not consider player behavior when forming teams. Reports about player behavior, including toxicity or negative actions, are generally handled separately through the game's player behavior systems, such as the Tribunal or automated systems for detecting unsportsmanlike conduct.
If a player is reported frequently for toxic behavior, they may face consequences such as chat restrictions, temporary suspensions, or other penalties, depending on the severity and frequency of their negative actions. However, this does not necessarily affect their matchmaking in terms of skill level or the quality of teammates they are matched with in future games.
It's important to note that while reports for negative behavior are taken seriously by the game's system, the matchmaking algorithm primarily focuses on creating balanced teams in terms of skill level to ensure fair and competitive matches. This approach is designed to provide players with a positive gaming experience based on their abilities rather than their behavior.
If you encounter toxic players in your games, it's recommended to use the in-game reporting tools and let the player behavior systems handle those reports. The matchmaking system itself is not influenced by player reports in terms of team composition